What can I do to win an assault charge?

Well it sounds like the force that you used was not proportional to the force that she used, so you may have a problem.

If you hit her first you are probably guilty of the assault. You should retain a good criminal lawyer to get an ACD or Disorderly Conduct violation.

You need to hire a lawyer before you make a wrong move, like open your mouth to the wrong folks and incriminate yourself. Ever heard of the right to remain silent?

It's too late to avoid anything. Prepare for the worse and hire an attorney.

If you put her in the hospital, expect to be criminally prosecuted. Hire a lawyer immediately and hire a private investigator to get witness statements. When someone touches your face, you don't get a free pass to completely obliterate her in the name of "self-defense". Your defensive actions must be reasonable under the circumstances. You're going to need an experienced criminal defense attorney to sell it.

Hire a lawyer and stop talking about the fight or your boxing.

Get yourself a lawyer. The sooner the better, i.e., don't wait until charges are filed or after you have been arrested. Also, don't beat up the lawyer.

Nothing you cannot use your boxing skills against one who has no skill much less a woman. You are probably going to be charged with felony assault or the like.

You will not avoid the assault charge, since that is what you did. Further, do to the extent of her injuries, it will be Assault 3 or higher.

Get a good lawyer. If it is a straight A&B you may be able to reach an Accord & Satisfaction, which is essentially you paying the victim and she agrees the charges get dropped and off of your record. This applies in MA, I have no idea if it is available in any other state. Make sure you hire a lawyer with a good local reputation.

Get an attorney and prepare a defense.

Depending on the severity of her injuries, you could be looking at a Third Degree Assault Charge. This is a felony and carries a possible punishment of 5 years in prison. There isn't a lot you can do to avoid being charged; that's out of your hands. The county attorney's office will review the police reports and any witness statements and make a determination whether there is probable cause to charge you with a crime. If so, the county attorney will sign the charging document called a Complaint and file it with the court. You would then most likely receive a copy of the Compliant in the mail along with a Summons advising you of your court date. The best thing you can do at this point is not talk to anyone - even the police. The police may try to contact you to "get your side of the story." You are under no obligation to talk to the police and it's probably in your best interest not to. If you are charged, that doesn't mean you're guilty of the crime. The state has to meet a much higher burden to convict someone of a criminal offense versus simply charging someone with a crime. Depending on the circumstances of the incident, you may be entitled to self-defense; however, a criminal defendant is not automatically entitled to rely on self-defense. The burden would fall on your shoulders to prove to the judge that you should be entitled to argue self-defense to a jury. There are limitations on when a criminal defendant is allowed to rely on self-defense and I would need to know more about the circumstances of the incident before I could give you a better idea of whether self-defense would be an option in your case.

You need a good criminal defense lawyer. I've won cases like this but they are not easy. Is the incident captured on surveillance?